Java® Performance Companion

**__Java® Performance Companion__** shows how to systematically and proactively improve Java performance with today’s advanced multicore hardware and complex operating system environments. The authors, who are all leading Java performance and Java HotSpot VM experts, help you improve performance by using modern software engineering practices, avoiding common mistakes, and applying tips and tricks gleaned from years of real-world experience. Picking up where Charlie Hunt and Binu John’s classic __Java Performance__ left off, this book provides unprecedented detail on two powerful Java platform innovations: the Garbage First (G1) garbage collector and the HotSpot VM Serviceability Agent. Coverage includes * Leveraging G1 to overcome limitations in parallel, serial, and CMS garbage collection * Understanding each stage of G1 GC collections, both young and old * Getting under the hood with G1 and efficiently fine-tuning it for your application * Identifying potential optimizations, interpreting experimental results, and taking action * Exploring the internals of the HotSpot VM * Using HotSpot VM Serviceability Agent to analyze, triage, and resolve diverse HotSpot VM issues * Troubleshooting out of memory errors, Java level deadlocks, and HotSpot VM crashes * Extending the Serviceability Agent, and using the Plugin for VisualVM * Mastering useful HotSpot VM command line options not covered in JavaTM Performance **__Java® Performance Companion__** can help you squeeze maximum performance and value from Java with JDK 8 or 9–for any application, in any environment. Register your product at informit.com/register for convenient access to downloads, updates, and corrections as they become available. Cover 1 Title Page 4 Copyright Page 5 Contents 6 Preface 10 Acknowledgments 12 About the Authors 16 Chapter 1 Garbage First Overview 18 Terminology 18 Parallel GC 19 Serial GC 21 Concurrent Mark Sweep (CMS) GC 22 Summary of the Collectors 24 Garbage First (G1) GC 25 G1 Design 27 Humongous Objects 29 Full Garbage Collections 29 Concurrent Cycle 30 Heap Sizing 31 References 31 Chapter 2 Garbage First Garbage Collector in Depth 32 Background 32 Garbage Collection in G1 33 The Young Generation 34 A Young Collection Pause 35 Object Aging and the Old Generation 36 Humongous Regions 36 A Mixed Collection Pause 39 Collection Sets and Their Importance 41 Remembered Sets and Their Importance 41 Concurrent Refinement Threads and Barriers 45 Concurrent Marking in G1 GC 47 Stages of Concurrent Marking 51 Initial Mark 51 Root Region Scanning 51 Concurrent Marking 51 Remark 53 Cleanup 53 Evacuation Failures and Full Collection 54 References 55 Chapter 3 Garbage First Garbage Collector Performance Tuning 56 The Stages of a Young Collection 56 Start of All Parallel Activities 58 External Root Regions 59 Remembered Sets and Processed Buffers 59 Summarizing Remembered Sets 61 Evacuation and Reclamation 64 Termination 64 Parallel Activity Outside of GC 65 Summarizing All Parallel Activities 65 Start of All Serial Activities 65 Other Serial Activities 66 Young Generation Tunables 67 Concurrent Marking Phase Tunables 69 A Refresher on the Mixed Garbage Collection Phase 71 The Taming of a Mixed Garbage Collection Phase 73 Avoiding Evacuation Failures 76 Reference Processing 77 Observing Reference Processing 77 Reference Processing Tuning 79 References 82 Chapter 4 The Serviceability Agent 84 What Is the Serviceability Agent? 85 Why Do We Need the SA? 85 SA Components 86 SA Binaries in the JDK 86 JDK Versions with Complete SA Binaries 86 How the SA Understands HotSpot VM Data Structures 87 SA Version Matching 88 The Serviceability Agent Debugging Tools 89 HSDB 89 HSDB Tools 97 CLHSDB 117 Some Other Tools 120 Core Dump or Crash Dump Files 125 Debugging Transported Core Files 126 Shared Library Problems with the SA 126 Eliminate Shared Library Problems 127 System Properties for the Serviceability Agent 128 Environment Variables for the Serviceability Agent 129 JDI Implementation 130 Extending Serviceability Agent Tools 132 Serviceability Agent Plugin for VisualVM 134 How to Install the SA-Plugin in VisualVM 135 How to Use the SA-Plugin 135 SA-Plugin Utilities 136 Troubleshooting Problems Using the SA 140 Diagnosing OutOfMemoryError 140 Diagnosing a Java-Level Deadlock 148 Postmortem Analysis of a HotSpot VM Crash 153 Appendix: Additional HotSpot VM Command-Line Options of Interest 162 Index 172 A 172 B 172 C 172 D 174 E 174 F 174 G 174 H 175 I 175 J 175 L 176 M 176 N 176 O 177 P 177 R 177 S 178 T 180 U 180 V 180 W 180 X 180 Y 181 Java(r) Performance Companion" shows how to systematically and proactively improve Java performance with today s advanced multicore hardware and complex operating system environments. The authors, who are all leading Java performance and Java HotSpot VM experts, help you improve performance by using modern software engineering practices, avoiding common mistakes, and applying tips and tricks gleaned from years of real-world experience. Picking up where Charlie Hunt and Binu John s classic "Java Performance" left off, this book provides unprecedented detail on two powerful Java platform innovations: the Garbage First (G1) garbage collector and the HotSpot VM Serviceability Agent. Coverage includes Leveraging G1 to overcome limitations in parallel, serial, and CMS garbage collection Understanding each stage of G1 GC collections, both young and old Getting under the hood with G1 and efficiently fine-tuning it for your application Identifying potential optimizations, interpreting experimental results, and taking action Exploring the internals of the HotSpot VM Using HotSpot VM Serviceability Agent to analyze, triage, and resolve diverse HotSpot VM issues Troubleshooting out of memory errors, Java level deadlocks, and HotSpot VM crashes Extending the Serviceability Agent, and using the Plugin for VisualVM Mastering useful HotSpot VM command line options not covered in Java Performance " " "Java(r) Performance Companion" can help you squeeze maximum performance and value from Java with JDK 8 or 9 for any application, in any environment. Register your product at (http://informit.com/register) informit.com/register for convenient access to downloads, updates, and corrections as they become available.